Jackson Heights used to be one of the few New York neighborhoods left to buy a great co-op apartment for a good deal. The prewar cooperatives there are known for their private, interior courtyards, and this building — The Towers, at 33-27 80th Street — has one of the best, spanning almost an entire city block. But it looks like this neighborhood is a bargain no longer. A for sale by owner listing has hit the market for a seven-bedroom, four-bedroom apartment at The Towers asking $1.1 million. (It last sold in 2011 for $675,000.) It’s a huge apartment, with 1,500 square feet, and loads of beautiful prewar details. And windows from the bedrooms and kitchen offer a view down to the courtyard below.